Effluents containing organic and/or inorganic contaminants have to be purified for ecological and economic reasons. Such effluents are generated in various processes which employ polymeric naphthalenesulfonate-based condensates, e.g. as a dispersant in emulsion polymerizations. It would be desirable to be able to remove these polymeric materials from effluents so that they do not interfere with subsequent waste treatment. It would be especially desirable to additionally be able to recover the polymeric materials in a form and purity suitable for recycle or re-use.
A number of approaches have been tried for the removal of polymeric naphthalenesulfonate-based condensate from aqueous effluent. Chemical oxidation, biodegradation, flocculation, reverse osmosis and carbon adsorption are either unsuccessful in providing adequate removal, or are very expensive to implement.
Chemical Abstracts 97:12615 and 104:131988 disclose the extraction and exchange of alkyl sulfates and aryl sulfonates by solutions of trinonyloctadecylammonium chloride in mixtures of toluene and other co-solvents. Chemical Abstracts 92:29200 discloses the selective separation of benzenesulfonic acid from sulfuric acid by extraction with a solution of trioctylamine in xylene. Chemical Abstracts 100:162715 discloses the separation of aromatic sulfonic acids from sulfuric acid using solutions of primary, secondary and tertiary amines in various solvents. Chemical Abstracts 105:45188 discloses the use of a xylene solution of trioctylamine to separate the following from sulfuric acid: 3-nitrobenzenesulfonic acid, benzene-1,3-disulfonic acid, 1-nitronaphthalene-3,6,8-trisulfonic acid, and mixed naphtholsulfonic acids. In none of these cases were the species extracted polymeric molecules.
We now have discovered a process that is not only effective for removal of polymeric naphthalenesulfonate-based carbonyl condensate from effluents, but also is capable of recovering the condensate as a concentrate, and purifying that concentrate to provide material suitable for re-use.